Is coproc <command> the same as <command> &?

I have read that $coproc is different from $ & in that coproc will execute command in a sub-shell process. But when I tested it, it worked just like $ &. The test is as follow: First: test the behavior of $ &. 1. Run $nano & on *tty1* 1. On another tty, output from $ps -t tty1 --forest indicates nano process is child process of the -bash process (login bash shell process -> no sub-shell process was created) Second: test the behavior of $coproc 1. Run $coproc nano on *tty1* 1. On another tty, output from $ps -t tty1 --forest is the same as above (no sub-shell process was created) So is $coproc simply the same as $ &? The shell used was a **bash shell**